The Battle of Britain (German: Luftschlacht um England, lit. 'air battle for England') was a military campaign of the Second World War, in which the Royal Air Force (RAF) and the Fleet Air Arm (FAA) of the Royal Navy defended the United Kingdom against large-scale attacks by Nazi Germany's air force, the Luftwaffe. It was the first major military campaign fought entirely by air forces. It takes its name from the speech given by Prime Minister Winston Churchill to the House of Commons on 18 June 1940: "What General Weygand called the 'Battle of France' is over. I expect that the Battle of Britain is about to begin."
The Germans had rapidly overwhelmed France and the Low Countries in the Battle of France, leaving Britain to face the threat of invasion by sea. The German high command recognised the difficulties of a seaborne attack while the Royal Navy controlled the English Channel and the North Sea. The primary objective of the German forces was to compel Britain to agree to a negotiated peace settlement.
The British officially recognise the battle's duration as being from 10 July until 31 October 1940, which overlaps the period of large-scale night attacks known as the Blitz, that lasted from 7 September 1940 to 11 May 1941. German historians do not follow this subdivision and regard the battle as a single campaign lasting from July 1940 to May 1941, including the Blitz.
In July 1940, the air and sea blockade began, with the Luftwaffe mainly targeting coastal-shipping convoys, as well as ports and shipping centres such as Portsmouth. On 16 July, Hitler ordered the preparation of Operation Sea Lion as a potential amphibious and airborne assault on Britain, to follow once the Luftwaffe had air superiority over the Channel. On 1 August, the Luftwaffe was directed to achieve air superiority over the RAF, with the aim of incapacitating RAF Fighter Command; 12 days later, it shifted the attacks to RAF airfields and infrastructure. As the battle progressed, the Luftwaffe also targeted factories involved in aircraft production and strategic infrastructure. Eventually, it employed terror bombing on areas of political significance and on civilians. In September, RAF Bomber Command night raids disrupted the German preparation of converted barges, and the Luftwaffe's failure to overwhelm the RAF forced Hitler to postpone and eventually cancel Operation Sea Lion. The Luftwaffe proved unable to sustain daylight raids, but their continued night-bombing operations on Britain became known as the Blitz.
Germany's failure to destroy Britain's air defences and force it out of the conflict was the first major German defeat in the Second World War.
Strategic bombing during World War I introduced air attacks intended to panic civilian targets and led in 1918 to the merger of the British army and navy air services into the Royal Air Force (RAF). Its first Chief of the Air Staff, Hugh Trenchard, was among the military strategists in the 1920s, like Giulio Douhet, who saw air warfare as a new way to overcome the bloody stalemate of trench warfare. Interception was expected to be nearly impossible, with fighter planes no faster than bombers. Their slogan was that the bomber will always get through, and that the only defence was a deterrent bomber force capable of matching retaliation. Predictions were made that a bomber offensive would quickly cause thousands of deaths and civilian hysteria leading to capitulation. However, widespread pacifism following the horrors of the First World War contributed to a reluctance to provide resources.
Germany was forbidden a military air force by the 1919 Treaty of Versailles, and therefore air crew were trained by means of civilian and sport flying. Following a 1923 memorandum, the Deutsche Luft Hansa airline developed designs for aircraft such as the Junkers Ju 52, which could carry passengers and freight, but also be readily adapted into a bomber. In 1926, the secret Lipetsk fighter-pilot school began training Germans in the Soviet Union. Erhard Milch organised rapid expansion, and following the 1933 Nazi seizure of power, his subordinate Robert Knauss formulated a deterrence theory incorporating Douhet's ideas and Tirpitz's "risk theory". This proposed a fleet of heavy bombers to deter a preventive attack by France and Poland before Germany could fully rearm. A 1933–34 war game indicated a need for fighters and anti-aircraft protection as well as bombers. On 1 March 1935, the Luftwaffe was formally announced, with Walther Wever as Chief of Staff. The 1935 Luftwaffe doctrine for "Conduct of Air War" (Luftkriegführung) set air power within the overall military strategy, with critical tasks of attaining (local and temporary) air superiority and providing battlefield support for army and naval forces. Strategic bombing of industries and transport could be decisive longer-term options, dependent on opportunity or preparations by the army and navy. It could be used to overcome a stalemate, or used when only destruction of the enemy's economy would be conclusive. The list excluded bombing civilians to destroy homes or undermine morale, as that was considered a waste of strategic effort, but the doctrine allowed revenge attacks if German civilians were bombed. A revised edition was issued in 1940, and the continuing central principle of Luftwaffe doctrine was that the destruction of enemy armed forces was of primary importance.
The RAF responded to Luftwaffe developments with its 1934 Expansion Plan A rearmament scheme, and in 1936 it was restructured into Bomber Command, Coastal Command, Training Command and Fighter Command. The last was under Hugh Dowding, who opposed the doctrine that bombers were unstoppable: the invention of radar at that time could allow early detection, and prototype monoplane fighters were significantly faster. Priorities were disputed, but in December 1937, the Minister in charge of Defence Coordination, Sir Thomas Inskip, sided with Dowding that "The role of our air force is not an early knock-out blow" but rather was "to prevent the Germans from knocking us out" and fighter squadrons were just as necessary as bomber squadrons.
The Spanish Civil War (1936–1939) gave the Luftwaffe Condor Legion the opportunity to test air fighting tactics with their new aeroplanes. Wolfram von Richthofen became an exponent of air power providing ground support to other services. The difficulty of accurately hitting targets prompted Ernst Udet to require that all new bombers had to be dive bombers, and led to the development of the Knickebein system for night time navigation. Priority was given to producing large numbers of smaller aeroplanes, and plans for a long-range, four-engined strategic bomber were cancelled.
First stages of the Second World War
The early stages of the Second World War saw successful German invasions on the continent, aided decisively by the air power of the Luftwaffe, which was able to establish tactical air superiority with great effectiveness. The speed with which German forces defeated most of the defending armies in Norway in early 1940 created a significant political crisis in Britain. In early May 1940, the Norway Debate questioned the fitness for office of the British Prime Minister Neville Chamberlain. On 10 May, the same day Winston Churchill became British Prime Minister, the Germans initiated the Battle of France with an aggressive invasion of French territory. RAF Fighter Command was desperately short of trained pilots and aircraft. Churchill sent fighter squadrons, the Air Component of the British Expeditionary Force, to support operations in France, where the RAF suffered heavy losses. This was despite the objections of its commander Hugh Dowding that the diversion of his forces would leave home defences under-strength.
After the evacuation of British and French soldiers from Dunkirk and the French surrender on 22 June 1940, Hitler mainly focused his energies on the possibility of invading the Soviet Union. He believed that the British, defeated on the continent and without European allies, would quickly come to terms. The Germans were so convinced of an imminent armistice that they began constructing street decorations for the homecoming parades of victorious troops. Although the British Foreign Secretary, Lord Halifax, and certain elements of the British public favoured a negotiated peace with an ascendant Germany, Churchill and a majority of his Cabinet refused to consider an armistice. Instead, Churchill used his skilful rhetoric to harden public opinion against capitulation and prepare the British for a long war.